In order to retard the acidification of the water of lakes, streams and similar bodies that is a consequence of acid rain and snow that is in turn caused by the burning of sulfur containing fuels, it is well known to add lime to the water in different ways. This lime is presently conventionally added in several different ways that are more or less efficient. For instance, it has been discovered that the lime, in order to be dissolved in the water, and thereby neutralizing the acid, must be added to the work as particles having a very small particle size, since the particles otherwise receive a coating preventing further solvation. The lime thus has its greatest effect if it is spread or added to the water in the form of lime flour. Regretfully, there have been no satisfactory methods or devices for continuously adding lime flour to a water stream. Instead, the adding of lime has been accomplished by incremental additions made from time to time, with consequent great variations in ph-value. This is not only undesirable from a biological viewpoint but has also meant that the added lime has not been used to its full extent.